Field of Invention
The present invention relates to a programmable power supply, and more specifically relates to a control circuit and a method for controlling the programmable power supply.
Description of the Related Art
The programmable power supply provides the output voltage which is programmable, such as 5V˜20V. The present invention provides a programmable frequency modulation function for a power supply with the programmable output voltage. The frequency modulation function is developed for saving the power during the light load operation. The detail skill of the frequency modulation function for the power supply can be found in the prior arts of “PWM controller having off-time modulation for power converter”, U.S. Pat. No. 6,545,882; “pulse width modulation controller having frequency modulation for power converter”, U.S. Pat. No. 6,597,159.